Apparatus and method for supplying a continuous web of crimped sheet material

ABSTRACT

An apparatus for supplying a continuous web of crimped sheet material ( 2 ) to a rod forming device comprises:—a winding unit ( 3 ) for unwinding the sheet material from a bobbin ( 21 ) on which the sheet material is provided;—a crimping unit ( 7 ) for crimping the sheet material,—a cutting unit ( 5 ) for cutting the continuous web of sheet material ( 2 ) to a predetermined width, the cutting unit ( 5 ) being arranged upstream of the crimping unit ( 7 ) when viewed in the direction of transport of the sheet material ( 2 ); and—a control unit ( 9 ) for controlling the various units of the apparatus in response to sensor signals received from the respective units.

The present invention relates to an apparatus and method for supplying acontinuous web of crimped sheet material.

An apparatus of this type is known, for example, in the field ofproduction of filters for smoking articles such as cigarettes. Thesefilters are typically made either from cellulose acetate tow or from acrimped sheet material, for example from paper. The crimped paper issupplied to a filter making device in form of a continuous web. Thefilter making device forms a filter rod from the continuous web ofcrimped paper supplied to the filter making device, and subsequentlycuts the filter rod into discrete filters of a predetermined length.

An apparatus for supplying a continuous web of crimped paper to a filtermaking device is known. In the prior art apparatus, the outlet of thecrimping unit is arranged so as to directly feed the crimped paper tothe filter making device. A control unit controls the various units ofthe apparatus and its operation, allowing little flexibility forvariation, e.g. with respect to manufacture of different types offilters.

It would be desirable to provide an apparatus which provides forenhanced flexibility with respect to various types and properties offilters that can be made using the crimped sheet material supplied bythe apparatus. This would provide enhanced productivity and costefficiency for meeting a variety of consumer needs.

In one aspect, the present invention provides an apparatus for supplyinga continuous web of crimped sheet material to a rod forming device. Theapparatus comprises a winding unit for unwinding the sheet material froma support on which the sheet material is provided, such as a bobbin, anda crimping unit for crimping the sheet material. The apparatus furthercomprises a cutting unit for cutting the continuous web of sheetmaterial to a predetermined width, and a control unit for controllingthe various units of the apparatus in response to sensor signalsreceived from the respective units.

The cutting unit is arranged upstream of the crimping unit when viewedin the direction of transport of the sheet material. This aspect isadvantageous since it allows cutting of the sheet material to differentwidths, which may for example allow to control the density of a filterrod. For this purpose, the cutting elements are displaceable in adirection perpendicular to the direction of transport of the sheetmaterial. Preferably, the cutting elements are symmetricallydisplaceable relative to the center line of the path along which thesheet material is transported through the apparatus. This allows cuttingthe sheet material of the web to a desired width and offers manyadvantages.

For example, the filters of regular filter cigarettes have a diameter ofabout 7.6 millimeters (mm), while the filters of so-called “slimcigarettes” have a diameter of about 7.1 millimeters (mm). Accordingly,when a web of sheet material has been processed for the production offilters for regular filter cigarettes and it is now desired to switch tothe production of filters for slim cigarettes, up to now the bobbincarrying the web for the filters of regular filter cigarettes isreplaced with a bobbin carrying a web having the width required for thefilters of slim filter cigarettes. This replacement of the bobbin is acomparatively laborious and time consuming process. One advantage of theembodiment of the apparatus comprising the afore-described cutting unitis that such replacement of the bobbin is no longer required. Instead,the cutting unit can be adjusted to cut the sheet material for theproduction of filters for regular filter cigarettes to the widthrequired for the filters of slim filter cigarettes as the web of sheetmaterial passes the cutting unit.

A further advantage of the cutting unit is that it allows for an easyvariation of the resistance to draw. By cutting the sheet material to asmaller width, the amount of crimped sheet material contained in thefilter is reduced whereby the resistance to draw is lowered given thatthe other parameters, for example an amount of add-on material dispensedas described further below, remain unchanged. Also, if a particularresistance to draw is desired and a specific sheet material is to beprocessed the sheet material can be cut to a width which is such thatafter the crimping and rod formation results in the desired resistanceto draw. Accordingly, this allows the processing of different types ofsheet materials, for example paper or plastic film, as well as ofdifferent widths of sheet materials.

In accordance with another aspect of the invention, the apparatusfurther comprises a dispensing unit for adding add-on material to thesheet material. The dispensing unit is arranged downstream of thecrimping unit when viewed in the direction of transport of the sheetmaterial, and upstream of a rod forming device to which the crimpedsheet material is supplied. Thus, add-on material can be added to thecrimped sheet material before the crimped sheet material is supplied toa rod forming device, for example to a filter making device.Alternatively, the rod forming device may be comprised in the apparatusaccording to the invention.

Adding the add-on material after crimping is advantageous. For example,because the add-on material is added to the already crimped sheetmaterial, the add-on material or at least a substantial amount thereofis retained in or on the crimped structures of the sheet material. Thecrimped sheet material with the add-on material is subsequently suppliedto the rod forming device where a rod of filter material is formed whichis then cut to size to form the individual filters having apredetermined length.

The term “sheet material” in this respect is meant to comprise any flatweb of a material suitable for the production of filters for smokingarticles, such as for example paper or plastic films. The sheet materialcan be either a single-layer sheet material or can be a multi-layersheet material.

The term “add-on material” includes, for example, liquid, gel-like orpasty materials, as well as particulate materials comprising, forexample, discrete particles, such as bulk material, powder, granules orthe like, and objects suitable for inclusion into a cigarette filter,such as capsules or beads and elongate material, as for example, thread.Preferably, the add-on material is a particulate material.

The addition of add-on material to the crimped sheet material maygenerally serve various purposes. For example, it may serve the purposeof adding to the smoke drawn in by a consumer through the filter. Forexample, the add-on material may comprise menthol, tobacco or otherdesired flavors. Alternatively or in addition, the add-on material mayserve to remove or alter at least part of the gaseous or solidconstituents of the smoke. For example, the added particulate materialmay comprise activated carbon granules.

Also, the resistance to draw of the final filter can be varied by addingthe add-on material. For example, by variation of the amount of add-onmaterial, for example particulate material, added to the sheet materialper unit of sheet material the resistance to draw can be lowered orraised.

The resistance to draw can also be varied by other capabilities of theapparatus, thus increasing flexibility of the apparatus according to theinvention. Due to the apparatus being capable of processing differenttypes of sheet material the resistance to draw can be varied throughselection of the type of sheet material processed. As an example, it ispossible to select paper or plastic film. Also, single layer sheetmaterials or multi-layer sheet materials can be selected. Still further,due to the apparatus being capable of processing sheet materials havingdifferent thicknesses the resistance to draw can be varied throughselection of the thickness of the sheet material processed by theapparatus. Yet further, due to the apparatus being capable of processingsheet materials having different widths the resistance to draw can bevaried through selection of the width of the sheet material processed bythe apparatus. The width of the sheet material is related to the densityof the crimped sheet material in the filter after rod formation.Therefore, the apparatus according to the invention is very flexible andallows the supply of crimped sheet material which allows the productionof filters of a large variety of types and properties. In addition, anapparatus according to the invention is particularly advantageous as thecost for manufacture filters comprising crimped sheet material istypically lower than the cost for manufacture of filters comprisingcellulose acetate tow.

According to an aspect of the invention, changing the resistance to drawof a filter is done by adapting the cut width of the sheet material.Changing the resistance to draw of a filter may comprise the step ofmeasuring a filter parameter and generating a signal indicative of themeasured filter parameter. The cut width of the sheet material may thenbe adapted in response to the signal.

Preferably, a filter parameter to be measured for the adaption of thecut width of the sheet material comprises at least one of, but is notlimited to: resistance to draw, rod firmness, weight, transparency,density and moisture content.

According to another aspect of the apparatus according to the invention,the crimping unit comprises a first pair of crimping rollers forengaging and crimping the continuous web of sheet material beingtransported between them. The crimping rollers have a surface which isprovided with means adapted to crimp the sheet material in the directionof transport of the sheet material. Preferably, the crimping rollershave a surface which is provided with means adapted to crimp the sheetmaterial in the longitudinal direction of the sheet material. By way ofexample, the means adapted to crimp the sheet material in the directionof transport of the sheet material may comprise a structure on thesurface of the rollers. In particular such a structure may comprise forexample crests and troughs running circumferentially about the axis ofrotation of the rollers. The sheet material is crimped by transferringthe structure to the sheet material as it passes between the rollers.The grooved structure transferred to the sheet material is particularlysuitable to receive the add-on material, in particular in case theadd-on material is a particulate material, or comprises capsules orbeads. Crimping the sheet material in the longitudinal direction alsoreduces the stability of the sheet material in a transverse direction.Thus, the subsequent formation of the rod (compression of the sheetmaterial into a cylindrical form) which is then cut to form theindividual filters is facilitated.

In accordance with another aspect of the invention, the crimping unitcomprises a second pair of crimping rollers for engaging and crimpingthe continuous web of sheet material being transported between them. Thecrimping rollers of the second pair of crimping rollers have a surfacewhich is provided with means adapted to crimp the sheet material in adirection transverse to the direction of transport of the sheetmaterial. The term “transverse to the direction of transport of thesheet material” is to be understood to include directions other thanperpendicular to the direction of transport of the sheet material.Preferably, the crimping rollers have a surface which is provided withmeans adapted to crimp the sheet material in a direction perpendicularto the direction of transport. By way of example, the means adapted tocrimp the sheet material in the direction transverse to the direction oftransport of the sheet material may comprise a structure on the surfaceof the rollers. This structure may comprise crests and troughs runningin a direction parallel to the axis of rotation of the rollers. Thisstructure is preferably provided on the entire surface of the rollers,so that the sheet material is crimped by transferring the structure ofthe rollers to the sheet material as it passes between the rollers.Alternatively, in some applications, it may be sufficient to crimp thesheet material only in sections in a transverse direction, such thatsome sections are crimped and others remain uncrimped in a transversedirection.

According to yet a further aspect of the invention, the crimping unitcomprises both a first pair of crimping rollers having a surface beingprovided with means adapted to crimp the sheet material in alongitudinal direction relative to the direction of transport of thesheet material, and a second pair of crimping rollers having a surfacebeing provided with means adapted to crimp the sheet material in adirection transverse to the direction of transport of the sheetmaterial. This embodiment allows both the crimping of the sheet materialin the longitudinal direction as well as in the transverse direction,resulting in a specific pattern being transferred to the sheet materialas the sheet material passes between the first and second pairs ofrollers. The structure on the surface of the respective pair of rollerscan be embodied as described above.

For any of the afore-described embodiments the add-on material added tothe crimped sheet material by the dispensing unit is preferablydispensed into the structure created in the crimped sheet material, forexample into the longitudinally running troughs, into the transverselyrunning troughs, or into the depressions of the pattern generated by thefirst and second pairs of rollers. This is particularly advantageous incase the add-on material is a particulate material. The particulatematerial dispensed into these troughs or depressions is retained thereinas the crimped sheet material is subsequently fed into the rod formingdevice where the crimped sheet material is then compressed to form arod.

According to yet another aspect of the invention, the winding unit maycomprise a motor for driving the bobbin on which the sheet material isprovided, and a brake. The control unit controls the motor and the brakein a manner such as to prevent the continuous web of sheet material fromrupturing. In the state of the art, so far, the sheet material is pulledthrough the apparatus by the crimping rollers or by additional driverollers of the crimping unit. According to the present invention, themotor of the winding unit assists in the unwinding of the sheet materialfrom the bobbin which is particularly advantageous in case the sheetmaterial is fragile. A fragile sheet material is prone to rupturing uponapplication of too high a pulling force by the rollers pulling the sheetmaterial through the apparatus. The occurrence of an excessively highpulling force can thus be avoided. Preferably, the control unit receivesa signal indicative of the actual tension of the sheet material. Thissignal can be processed and the motor of the winding unit can becontrolled in response. Also, the brake of the winding unit can becontrolled by the control unit. As the bobbin is close to getting empty,that is, at the time there is only little sheet material left on thebobbin, rotation of the bobbin must be stopped. The brake serves toachieve a smooth braking profile in order to avoid rupturing of thesheet material during this phase.

In accordance with a still further aspect of the invention, theapparatus further comprises a tensioning unit comprising a controlledactuator for applying and maintaining a predetermined tension to thesheet material during the transport of the sheet material through theapparatus. While passive tensioning units are known in the art, atensioning unit comprising a controlled actuator is advantageous in thatit allows active control of the tension applied to the sheet material.For example, known prior art tensioning units comprise a passivetensioning element having a fixed mass or weight through which tensionis applied to the sheet material, however, this tension cannot beactively controlled. By way of example, the controlled actuator inaccordance with this aspect of the invention may be a controlledpneumatic actuator, a controlled hydraulic actuator, a controlledelectric actuator or may be any suitable other type of controlledactuator, in order to actively control the tension applied to the sheetmaterial.

In accordance with yet a further aspect of the invention, the apparatusfurther comprises a softening unit which is arranged upstream of thecrimping unit. The softening unit serves to facilitate the crimpingoperation by softening the sheet material to be crimped. By way ofexample, the softening unit may comprise a heat source for raising thetemperature of the sheet material to be crimped. Such a softening unitcomprising a heat source is particularly advantageous for plastic sheetmaterial. An increase in temperature of the plastic sheet materialsoftens the sheet material and may thus facilitate crimping of the sheetmaterial. Any conventional heat source can be used for that purpose,such as for example an infrared radiator. Alternatively or incombination, the softening unit may comprise a moisture control meanswhich is capable of raising or lowering the moisture content of thesheet material. For example, for raising the moisture content of papersheet material, the moisture control means may comprise a nozzlearrangement for moisturizing the paper sheet material to be crimped.Should the moisture content be too high, the heat source may beactivated to lower the moisture content of the paper sheet material.

Further advantageous aspects of the invention will become apparent fromthe following description of an embodiment of the apparatus according tothe invention with the aid of the drawings in which:

FIG. 1 shows a schematic representation of an embodiment of theapparatus according to the invention;

FIG. 2 shows a schematic representation of a first embodiment of twocrimping rollers of the apparatus according to the invention; and

FIG. 3 shows a schematic representation of a second embodiment of twocrimping rollers (upper right) of the apparatus according to theinvention, as well as of two schematic (upper and lower left)arrangements of crests and troughs provided on the surface of thecrimping rollers.

In FIG. 1 an embodiment of the apparatus according to the invention isshown in a schematic representation. The apparatus comprises a drivingunit 1 comprising driving rollers 10 for drivingly engaging andtransporting a sheet material 2 through the apparatus. For example, thesheet material 2 may be paper or a suitable plastics film. The sheetmaterial 2 is stored as a reel 20 on a bobbin 21 from which the sheetmaterial 2 can be unwound with the aid of a winding unit 3.

Winding unit 3 comprises a motor 30 and a brake 31 capable of acting onthe bobbin 21 so as to apply an additional driving or braking force tothe bobbin 21. This is described in more detail below. A sensor 32 isprovided in order to detect the distance between the sensor 32 and theoutermost layer of the reel 20 so as to determine whether there issufficient sheet material left on the bobbin 21 to continue operation.

The sheet material 2 is transported through the apparatus in the form ofa web. A number of transport rollers 11 are provided along the path ofthe web of sheet material 2 through the apparatus. These transportrollers 11 serve to clamp or guide the web of sheet material 2 on itspath through the apparatus.

The apparatus further comprises a tensioning unit 4 for applying andmaintaining a predetermined tension to the web of sheet material 2 as itis transported through the apparatus. For this purpose, tensioning unit4 comprises a controlled actuator 40 which can be actively controlled inorder to always maintain the desired predetermined tension to the web ofsheet material 2 even if the conditions during operation change.

The apparatus further comprises a cutting unit 5 for on-line cutting thesheet material 2 to the desired width. As has been explained above, ifthe width of the sheet material 2 to be supplied by the apparatus is tobe changed (for example, due to a switching from the production offilters for regular filter cigarettes to the production of filters forslim cigarettes, or for any other reason, see above) it is no longernecessary to interrupt production and to change the bobbin 21 carryingthe reel 20, but rather the cutting unit 5 allows to cut the sheetmaterial 2 on-line to the desired width. The cutting unit 5 will bedescribed in more detail below.

The apparatus further comprises a softening unit 6 for raising thetemperature of the sheet material 2. The softening unit is arrangedupstream of a crimping unit 7 for crimping the sheet material 2. Thesoftening unit 6 assists in softening the sheet material 2 to facilitatecrimping of the sheet material 2. As has already been explained above,softening unit 6 may comprise a heat source such as an infraredradiator, however, it may also comprise any other type of radiatorsuitable for this purpose. Such heat source is particularly advantageousin case the sheet material 2 is a plastic sheet material. Alternativelyor in combination, softening unit 6 may comprise a moisture controlmeans which is capable of raising or lowering the moisture content ofthe sheet material 2. This is particularly advantageous in case thesheet material 2 is a paper sheet material. For example, for raising themoisture content of the paper sheet material, the moisture control meansmay comprise a nozzle arrangement for moisturizing the paper sheetmaterial to be crimped. Should the moisture content be too high, theheat source may be activated to lower the moisture content of the papersheet material.

As already mentioned, the apparatus further comprises crimping unit 7for crimping the sheet material 2. Crimping unit 7 may comprise alongitudinal crimping unit 70, or a lateral crimping unit 71, or both alongitudinal crimping unit 70 and a lateral crimping unit 71. Thelongitudinal crimping unit 70 as well as the lateral crimping unit 71may comprise one or more pairs of rollers, as will be described in moredetail below with the aid of FIG. 2 and FIG. 3.

The apparatus further comprises a dispensing unit 8 for adding add-onmaterial to the sheet material 2. As already mentioned, preferably theadd-on material is a particulate material. Dispensing unit 8 is arrangeddownstream of crimping unit 7 when viewed in the direction of transportof the sheet material 2, and upstream of a rod forming device to whichthe sheet material is supplied by the apparatus. Suitable rod formingdevices are well-known in the art and, therefore, they are not describedin detail.

Finally, the apparatus comprises a control unit 9 for controlling thevarious units, as this is indicated by the various dashed lines andarrows in FIG. 1.

In operation, the sheet material 2 stored as a reel 20 is unwound fromthe bobbin 21. Driving rollers 10 of driving unit 1 apply tractionforces to the web of sheet material 2 causing the sheet material 2 to beunwound from reel 20 stored on bobbin 21. However, these forces may varyto some extent. Since rupturing of the sheet material 2 must be avoided,as control unit 9 receives a signal from driving unit 1 representativeof high traction forces, control unit 9 may cause motor 30 to applyadditional torque to bobbin 21 in order to prevent the sheet material 2from rupturing. In a similar manner, control unit 9 may cause brake 31to slow down the rotational speed of bobbin 21 so as to increase tensionof the sheet material 2 should the tension have become too low. Also, atthe time there is only a little amount of sheet material 2 left on reel20—this being detected by sensor 32—brake 31 assists in controlling therotational speed of bobbin 21 to avoid rupturing of the sheet material 2during the stopping phase.

As already mentioned above, tensioning unit 4 comprising controlledactuator 40 assists in applying and maintaining a predetermined tensionof the sheet material 2. This enables a reliable transport of the sheetmaterial 2 through the apparatus and on the other hand prevents thesheet material 2 from rupturing by actively controlling the tension ofthe sheet material 2.

In the further path of the sheet material 2 through the apparatuscutting unit 5 may cut the sheet material 2 to the desired width in casethe sheet material 2 unwound from reel 20 does not already have therequired width. For that purpose, cutting unit 5 may comprise twolaterally adjustable cutting wheels 50 (only one of them being shown inFIG. 1) which may be adjusted in a direction perpendicular to thedirection of transport of the sheet material 2. Preferably, the cuttingwheels 50 are symmetrically displaceable relative to a center line ofthe path of the sheet material 2.

Turning back to FIG. 1, with the aid of softening unit 6 the sheetmaterial may be heated or moisturized prior to getting crimped in orderto soften the sheet material 2 to facilitate crimping.

The sheet material 2 then enters crimping unit 7 which may compriseeither a longitudinal crimping unit 70, or a lateral crimping unit 71,or both a longitudinal crimping unit 70 and a lateral crimping unit 71.For example, lateral crimping unit 71 comprises a pair of crimpingrollers 710 as shown in FIG. 2. As the sheet material 2 passes throughcrimping rollers 710 it is crimped in a direction transverse to thedirection of transport of the sheet material 2. In the embodiment shownin FIG. 2, the sheet material 2 is crimped in a direction perpendicularto the direction of transport, as this can be seen from the arrangementof the crests 711 and troughs 712 on the surface of crimping rollers710. The dashed lines 713 on sheet material 2 shown in FIG. 2 areintended to indicate the grooves that have been crimped into the sheetmaterial 2 in the direction of dashed lines 713.

Longitudinal crimping unit 70 may also comprise a pair of rollers 700,as this is shown in FIG. 3 (upper right). However, in contrast tolateral crimping unit 71 the rollers 700 of longitudinal crimping unit70 may comprise crests 701 and troughs 702 on the surface of crimpingrollers which are arranged as this is shown schematically in the upperleft representation of FIG. 3. The lower left representation shows analternative arrangement of crests 701 and troughs 702, however, althoughthe peaks are shown to have a sharp contour they may be rounded. As thesheet material 2 passes through the pair of rollers 700 it is crimped inthe longitudinal direction, that is, in the direction of transport ofthe sheet material 2. In the left hand representations of FIG. 3, thesheet material 2 passes out of the plane of the drawings towards theobserver.

Of course, the apparatus may also comprise both a longitudinal crimpingunit 70 and a lateral crimping unit 71. This results in a pattern oflongitudinally and transversely arranged recesses in the sheet material.

Subsequently, the sheet material passes through the dispensing unit 8where the add-on material, preferably particulate matter, is added tothe crimped sheet material 2. The particulate matter may be dispensedinto the grooves crimped into the sheet material 2 by the crests 711 or701 of the rollers 71 or 70, or into the recesses, respectively.

The sheet material to which the particulate material has been added maythen be drawn through a converging funnel to form a rod of compressedsheet material containing the particulate matter. This rod of compressedsheet material can then be processed by a filter making apparatus in theconventional manner.

1. Apparatus for supplying a continuous web of crimped sheet material toa rod forming device, the apparatus comprising winding unit or unwindingthe sheet material from a bobbin on which the sheet material isprovided; a crimping unit for crimping the sheet material, a cuttingunit for cutting the continuous web of sheet material to a predeterminedwidth, the cutting unit being arranged upstream of the crimping unitwhen viewed in the direction of transport of the sheet material; and acontrol unit for controlling the various units of the apparatus inresponse to sensor signals received from the respective units, whereinthe cutting unit comprises cutting elements displaceable in a directionperpendicular to a direction of transport of the sheet material foradjusting the width of the sheet material.
 2. Apparatus according toclaim 1, further comprising a dispensing unit for adding an add-onmaterial to the sheet material, wherein the dispensing unit is arrangeddownstream of the crimping unit when viewed in the direction oftransport of the sheet material, and upstream of the rod forming deviceto which the crimped sheet material is supplied.
 3. Apparatus accordingto claim 1, wherein the crimping unit comprises a first pair of crimpingrollers for engaging and crimping the continuous web of sheet materialbeing transported between them, the crimping rollers having a surfaceadapted to crimp the sheet material in the direction of transport of thesheet material.
 4. Apparatus according to claim 1, wherein the crimpingunit comprises a second pair of crimping rollers for engaging andcrimping the continuous web of sheet material being transported betweenthem, the crimping rollers having a surface adapted to crimp the sheetmaterial in a direction transverse to the direction of transport of thesheet material.
 5. Apparatus according to claim 3, wherein the crimpingunit comprises both the first pair of crimping rollers having a surfaceadapted to crimp the sheet material in a longitudinal direction relativeto the direction of transport of the sheet material, and a second pairof crimping rollers having a surface adapted to crimp the sheet materialin a direction transverse to the direction of transport of the sheetmaterial.
 6. Apparatus according to claim 1, wherein the winding unitcomprises a motor for driving the bobbin on which the sheet material isprovided and a brake, the control unit controlling the motor and thebrake in a manner such as to prevent the continuous web of sheetmaterial from rupturing.
 7. Apparatus according to claim 1, furthercomprising a tensioning unit comprising a controlled actuator forapplying and maintaining a predetermined tension to the sheet materialduring the transport of the sheet material through the apparatus. 8.Apparatus according to claim 1, further comprising a softening unit forsoftening the sheet material to be crimped, the softening unit beingarranged upstream of the crimping unit when viewed in the direction oftransport of the sheet material.
 9. Apparatus according to claim 1,wherein the sheet material is one of paper, plastic, metal or is alaminate of at least two of paper, plastic and metal.
 10. Method forsupplying a continuous web of crimped sheet material to a rod formingdevice, the method comprising the steps of unwinding the sheet materialfrom a bobbin on which the sheet material is stored; transporting thesheet material to a crimping unit; cutting the sheet material to apredetermined width; crimping the sheet material; supplying the crimpedsheet material to the rod forming device, wherein cutting the sheetmaterial to a predetermined width is performed prior to crimping thesheet material; and varying the width of the sheet material bydisplacing cutting elements in a direction perpendicular to a directionof transport of the sheet material.
 11. Method according to claim 10,further comprising the step of adding an add-on material to the sheetmaterial, wherein adding the add-on material to the sheet material isperformed after crimping of the sheet material and prior to supplyingthe crimped sheet material to the rod forming device.
 12. Methodaccording to claim 10, wherein the step of varying the width of thesheet material comprises changing the resistance to draw of a filter.13. Method according to claim 12, wherein the step of changing theresistance to draw of a filter comprises the step of measuring a filterparameter, generating a signal indicative of the measured filterparameter and adapting the cut width of the sheet material in responseto the signal.
 14. Method according to claim 13, wherein the filterparameter comprises at least one of: resistance to draw, rod firmness,weight, transparency, density and moisture content.
 15. (canceled) 16.Apparatus according to claim 2, wherein the crimping unit comprises afirst pair of crimping rollers for engaging and crimping the continuousweb of sheet material being transported between them, the crimpingrollers having a surface adapted to crimp the sheet material in thedirection of transport of the sheet material.
 17. Method according toclaim 11, wherein the step of varying the width of the sheet materialcomprises changing the resistance to draw of a filter.
 18. Methodaccording to claim 12, further comprising the step of incorporating thefilter into a smoking article.